package myQueue;

class MyCircularQueue {
    private int[] elem;
    private int front;
    private int rear;
    public MyCircularQueue(int k) {
        this.elem = new int[k];
    }

    public boolean enQueue(int value) {
        if(isFull()){
            return false;
        } else {
            elem[rear] = value;
            rear = (rear + 1) % elem.length;
            return true;
        }
    }

    public boolean deQueue() {
        if(isEmpty()){
            return false;
        } else{
            front = (front +1) % elem.length;
            return true;
        }
    }

    public int Front() {
        if(isEmpty()){
            return -1;
        } else{
            return elem[front];
        }
    }

    public int Rear() {
        if(isEmpty()){
            return -1;
        } else{
            int index = (rear == 0) ? elem.length - 1 : rear - 1;
            return elem[index];
        }
    }

    public boolean isEmpty() {
        return front == rear;
    }

    public boolean isFull() {
        //采用了浪费一个格子的形式确定队列是否满
        return (rear + 1)%elem.length == front;
    }
}

